The present invention relates to a subframe for a motor vehicle.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Subframes for motor vehicles known in the art are usually formed by two spaced-apart cast joints, which are interconnected by means of a transverse member and/or a stiffening element. The subframe also includes longitudinal members, which are connected with both the cast joints and with the vehicle body. The cast joints or the longitudinal members have corresponding connection points for the arrangement of control arms. For the reception/fastening of drive aggregates so called motor bearings are used. These motor bearings serve for decoupling vibrations introduced by the aggregate and for absorbing forces and torques generated during driving operation. The motor bearings are fastenable on corresponding bearing connection points of the subframe. Such a subframe for a motor vehicle is for example described in DE 198 22 731 A1.
Depending on the type of the aggregate and dimension, the demands on the motor bearings differ, which is why the size and the position of the motor bearings on the subframe always vary.
A high variance of subframes or cast joints for receiving different aggregates and motor bearings is however not feasible for economic and technical reasons.
EP 1 837 268 therefore proposes a subframe, which can be extended by an adapter part, which provides at least one additional bearing site. The adapter part is formed integrally on the stiffening structure. Thus at least two further bearing sites can be provided in addition to the bearing sites provided on the subframe. This allows also receiving drive aggregates of higher classes on the subframe. In the case of smaller engines a stiffened element is used which is formed without the adapter parts. Preferably the adapter part is hereby formed as transverse member.
A disadvantage is that depending on the equipment and type of engine being used, cross struts or a stiffening element have to be provided which leads to the fact that a relatively large component has to be manufactured in multiple variants thus foregoing the advantage of high volume production.
A further significant disadvantage is that even though the proposed solution provides a certain modularity, the bearing position always remains unchanged. In contrast to an eight or twelve-cylinder V-engine, identically positioned connection points cannot be used for a four-cylinder inline engine. EP 1 837 268 merely proposes a further bearing position in addition to the structurally identical bearings, which are formed in the cast console. However these spaces can no longer be used due to the direction of extent of different aggregates.
It would therefore be desirable and advantageous to further develop a subframe for a motor vehicle while avoiding the mentioned disadvantages, so that the bearing position of the engine bearings on the cast joints can be varied while retaining the essential, components of the subframe.